Conventionally, one having a form of woven fabric has been abundantly used as an intermediate base material when producing a fiber reinforced plastic. In the woven fabric for reinforcement, a thin reinforcing fiber yarn is used for a warp and a weft so as to reduce crimp due to the interlacing of the warp and weft as much as possible to exhibit high intensity expression.
Since a thin yarn causes the low productivity of the yarn itself and woven fabric when the reinforcing fiber is particularly a carbon fiber yarn, the reinforcing woven fabric and has been mainly used for an airplane use or the like having large weight saving effect.
However, the low cost of the material is strongly hammered out due to the stagnation of the latest aircraft industry, and the appearance of inexpensive carbon fiber woven fabric has been desired.
Under such a condition, a carbon fiber flat yarn woven fabric obtained by interlacing thick carbon fiber yarns in a flat shape has been proposed in, for example, Japanese Patent Application Laid-Open (JP-A) No. 6-136632. Since the woven fabric is woven in large woven pitch by using the carbon fiber yarn of the thick fineness of inexpensive manufacture cost, the productivity of the woven fabric is also high, and the inexpensive woven fabric can be provided. Also, the high strength is exhibited since the crimp at the interlacing point of the weaving yarn is also small.
However, since a lot of multi-filament consisting of the carbon fiber converged by few sizing agent such that the yarn bundle section is the flat shape, the flat yarn bundle is crushed by the weaving step so as it makes the yarn narrower, and a gap is generated between the weaving yarns in the woven fabric. Therefore, the woven fabric is used and formed into a fiber reinforced composite material molded object (hereinafter, referred to as molded object), the molded object in which the resin is unevenly dispersed between the weaving yarns is obtained. The molded object having the high content of the carbon fiber is not obtained. Also, when the stress acts on the molded object, a portion in which the resin is unevenly dispersed becomes the starting point of destruction, and high mechanical property is not exhibited. Since a portion where a resin is unevenly dispersed in a molded object is greatly shrunk by the consolidation of the resin, a molded object in which the resin is unevenly dispersed is depressed, and unevenness is generated on the surface of the molded object.
Examples of the factors in which the gap is formed between the weaving yarns include the followings.
(1) A gap is generated around fine narrow yarn by the changing of the yarn width of a carbon fiber flat yarn itself.
(2) When a bobbin around which a carbon fiber yarn is wound is unwound, a temporal twist is mixed by the winding curl, and the twist part results in narrower, thereby the gap generated between the weaving yarns.
(3) A related position of a heddle for opening the warp and a dent is shifted, and the width of the warp becomes narrow. The gap is generated between the weaving yarns.
(4) When the weft is beat, the width of the weft becomes narrow, and the gap is generated between the wefts.
Conventionally, for such problems, the method for performing the rotational movement of many spherical bodies under a pressurization state to closed the opening point of the woven fabric after making the woven fabric is proposed in Japanese Patent Application Laid-Open (JP-A) No. 2-307965.
According to the method, since the yarn bundle of the weaving yarn is converged as the section of the bundle is almost a circular shape in the woven fabric in which the thin carbon fiber yarn having the number of filaments of about 3,000 is woven in the small weaving yarn pitch, the yarn width is widened by pushing the weaving yarn at the convex part of the spherical body, and the opening is closed.
However, in the woven fabric having large weaving yarn pitch like the flat yarn woven fabric consisting of the carbon fiber, the convex part of the spherical body (central part of the ball) may be located between the flat weaving yarns. Since the convex part of the spherical body is rolled between the weaving yarns in that condition, the operation for enlarging the gap between the weaving yarns acts, and the yarn width is narrowed on the contrary. Since the rotation of the spherical body is not lightly rotated by friction with a positioning mesh, the woven fabric slippage is easily generated by the movement of the spherical body in the flat yarn woven fabric where the binding force between the warp and the weft is weak and the woven fabric slippage is easily and simply generated.
Thereby, the above prior art has a fault, and the appearance of the producing method adding the improvement to the producing method and apparatus is desired when the flat yarn woven fabric made of the carbon fiber which has large weaving yarn pitch as the reinforcing fiber and easily generates the woven fabric slippage is used.
It is an object of the invention to solve the above conventional problems and provide the method and the apparatus for producing the reinforcing fiber woven fabric which has no opening between the weaving yarns and in which the reinforcing fiber is uniformly dispersed by adding an effective yarn width widening method in the producing step when producing the reinforcing fiber woven fabric using the flat yarn as the weaving yarn.